Actually Gaga's response to the Madonna thing initially was that it was ''retarded''. Also I don't think any Madonna fan feels treatened by Gaga, threatened about what exactly? Pop stars like Gaga come and go, Britney was in the exact same place 10 years ago, as was Cyndi in the 80s and Mariah in the 90s. Madonna hasn't lasted 30 years for nothing. Only until another female artist lasts as long as Madonna and is still having number 1 albums and sell out world tours 30 years into their career can someone say they feel treatened. Its rather laughable and immature to suggest thats the case. Gaga's success is nothing Madonna fans haven't seen before and I'm sure its nothing they won't see again in the future once the next big female blows up.
Actually, Gaga made the "retarded" comment regarding the suggestion that she had directly copied Express Yourself when writing BTW, before going on to say that she had merely used a chord progression that had been used in disco music for decades, and that she would have to be a complete idiot to think she'd get away with it. As nicmars said she has said many times how Madonna inspired her. What people don't seem to get is that Born This Way the album was practically Gaga's homage to the 80s, though she didn't go running around saying it. She has said how Madonna inspired her, but also artists like Bruce Springsteen and Iron Maiden. The cover clearly references 80s rock album covers. Also, the majority of the songs on BTW sound nothing like anything that Madonna has ever done. I can't imagine her doing something like You and I or Americano.
It seems people are having a go at Gaga because she's not creating something completely original, but Gaga has never said that that is what she aims to do. She brings together other genres and adds a Gaga-twist to them. 'Highway Unicorn' for example, brings together rock and dance music to create something that sounds really interesting but still clearly references its inspirations, and there's nothing out there now that sounds like it. Madonna has made a career of finding the new trends and bringing them to the mainstream and that's what she's good at, although judging by her last two albums, she's getting a bit slow, but luckily for her she's had thirty years to build up a fan base that will buy anything she puts out and go to every tour she does. But it's very clear that some Madonna fans are threatened by her. I can only guess it's because Gaga is the first credible threat- she can do everything Madonna can do, and in some cases she can do it better (song writing and her voice, whilst Madonna is the more natural dancer and general performer, in my opinion.)